NAME¶
gitattributes - defining attributes per path
SYNOPSIS¶
$GIT_DIR/info/attributes, .gitattributes
DESCRIPTION¶
A gitattributes file is a simple text file that gives attributes to pathnames.
Each line in gitattributes file is of form:
That is, a pattern followed by an attributes list, separated by whitespaces.
When the pattern matches the path in question, the attributes listed on the
line are given to the path.
Each attribute can be in one of these states for a given path:
Set
The path has the attribute with special value
"true"; this is specified by listing only the name of the attribute
in the attribute list.
Unset
The path has the attribute with special value
"false"; this is specified by listing the name of the attribute
prefixed with a dash - in the attribute list.
Set to a value
The path has the attribute with specified
string value; this is specified by listing the name of the attribute followed
by an equal sign = and its value in the attribute list.
Unspecified
No pattern matches the path, and nothing says
if the path has or does not have the attribute, the attribute for the path is
said to be Unspecified.
When more than one pattern matches the path, a later line overrides an earlier
line. This overriding is done per attribute. The rules how the pattern matches
paths are the same as in .gitignore files; see
gitignore(5).
When deciding what attributes are assigned to a path, git consults
$GIT_DIR/info/attributes file (which has the highest precedence),
.gitattributes file in the same directory as the path in question, and its
parent directories up to the toplevel of the work tree (the further the
directory that contains .gitattributes is from the path in question, the lower
its precedence). Finally global and system-wide files are considered (they
have the lowest precedence).
If you wish to affect only a single repository (i.e., to assign attributes to
files that are particular to one user’s workflow for that repository),
then attributes should be placed in the $GIT_DIR/info/attributes file.
Attributes which should be version-controlled and distributed to other
repositories (i.e., attributes of interest to all users) should go into
.gitattributes files. Attributes that should affect all repositories for a
single user should be placed in a file specified by the core.attributesfile
configuration option (see
git-config(1)). Attributes for all users on a
system should be placed in the $(prefix)/etc/gitattributes file.
Sometimes you would need to override an setting of an attribute for a path to
Unspecified state. This can be done by listing the name of the attribute
prefixed with an exclamation point !.
EFFECTS¶
Certain operations by git can be influenced by assigning particular attributes
to a path. Currently, the following operations are attributes-aware.
Checking-out and checking-in¶
These attributes affect how the contents stored in the repository are copied to
the working tree files when commands such as
git checkout and
git
merge run. They also affect how git stores the contents you prepare in the
working tree in the repository upon
git add and
git commit.
text
This attribute enables and controls end-of-line normalization. When a text file
is normalized, its line endings are converted to LF in the repository. To
control what line ending style is used in the working directory, use the eol
attribute for a single file and the core.eol configuration variable for all
text files.
Set
Setting the text attribute on a path enables
end-of-line normalization and marks the path as a text file. End-of-line
conversion takes place without guessing the content type.
Unset
Unsetting the text attribute on a path tells
git not to attempt any end-of-line conversion upon checkin or checkout.
Set to string value "auto"
When text is set to "auto", the path
is marked for automatic end-of-line normalization. If git decides that the
content is text, its line endings are normalized to LF on checkin.
Unspecified
If the text attribute is unspecified, git uses
the core.autocrlf configuration variable to determine if the file should be
converted.
Any other value causes git to act as if text has been left unspecified.
eol
This attribute sets a specific line-ending style to be used in the working
directory. It enables end-of-line normalization without any content checks,
effectively setting the text attribute.
Set to string value "crlf"
This setting forces git to normalize line
endings for this file on checkin and convert them to CRLF when the file is
checked out.
Set to string value "lf"
This setting forces git to normalize line
endings to LF on checkin and prevents conversion to CRLF when the file is
checked out.
Backwards compatibility with crlf attribute
For backwards compatibility, the crlf attribute is interpreted as follows:
crlf text
-crlf -text
crlf=input eol=lf
End-of-line conversion
While git normally leaves file contents alone, it can be configured to normalize
line endings to LF in the repository and, optionally, to convert them to CRLF
when files are checked out.
Here is an example that will make git normalize .txt, .vcproj and .sh files,
ensure that .vcproj files have CRLF and .sh files have LF in the working
directory, and prevent .jpg files from being normalized regardless of their
content.
*.txt text
*.vcproj eol=crlf
*.sh eol=lf
*.jpg -text
Other source code management systems normalize all text files in their
repositories, and there are two ways to enable similar automatic normalization
in git.
If you simply want to have CRLF line endings in your working directory
regardless of the repository you are working with, you can set the config
variable "core.autocrlf" without changing any attributes.
This does not force normalization of all text files, but does ensure that text
files that you introduce to the repository have their line endings normalized
to LF when they are added, and that files that are already normalized in the
repository stay normalized.
If you want to interoperate with a source code management system that enforces
end-of-line normalization, or you simply want all text files in your
repository to be normalized, you should instead set the text attribute to
"auto" for
all files.
This ensures that all files that git considers to be text will have normalized
(LF) line endings in the repository. The core.eol configuration variable
controls which line endings git will use for normalized files in your working
directory; the default is to use the native line ending for your platform, or
CRLF if core.autocrlf is set.
Note
When text=auto normalization is enabled in an existing repository, any text
files containing CRLFs should be normalized. If they are not they will be
normalized the next time someone tries to change them, causing unfortunate
misattribution. From a clean working directory:
$ echo "* text=auto" >>.gitattributes
$ rm .git/index # Remove the index to force git to
$ git reset # re-scan the working directory
$ git status # Show files that will be normalized
$ git add -u
$ git add .gitattributes
$ git commit -m "Introduce end-of-line normalization"
If any files that should not be normalized show up in
git status, unset
their text attribute before running
git add -u.
Conversely, text files that git does not detect can have normalization enabled
manually.
If core.safecrlf is set to "true" or "warn", git verifies if
the conversion is reversible for the current setting of core.autocrlf. For
"true", git rejects irreversible conversions; for "warn",
git only prints a warning but accepts an irreversible conversion. The safety
triggers to prevent such a conversion done to the files in the work tree, but
there are a few exceptions. Even though...
•
git add itself does not touch the files in the work tree, the next
checkout would, so the safety triggers;
•
git apply to update a text file with a patch does touch the files in the
work tree, but the operation is about text files and CRLF conversion is about
fixing the line ending inconsistencies, so the safety does not trigger;
•
git diff itself does not touch the files in the work tree, it is often
run to inspect the changes you intend to next
git add. To catch
potential problems early, safety triggers.
ident
When the attribute ident is set for a path, git replaces $Id$ in the blob object
with $Id:, followed by the 40-character hexadecimal blob object name, followed
by a dollar sign $ upon checkout. Any byte sequence that begins with $Id: and
ends with $ in the worktree file is replaced with $Id$ upon check-in.
filter
A filter attribute can be set to a string value that names a filter driver
specified in the configuration.
A filter driver consists of a clean command and a smudge command, either of
which can be left unspecified. Upon checkout, when the smudge command is
specified, the command is fed the blob object from its standard input, and its
standard output is used to update the worktree file. Similarly, the clean
command is used to convert the contents of worktree file upon checkin.
One use of the content filtering is to massage the content into a shape that is
more convenient for the platform, filesystem, and the user to use. For this
mode of operation, the key phrase here is "more convenient" and not
"turning something unusable into usable". In other words, the intent
is that if someone unsets the filter driver definition, or does not have the
appropriate filter program, the project should still be usable.
Another use of the content filtering is to store the content that cannot be
directly used in the repository (e.g. a UUID that refers to the true content
stored outside git, or an encrypted content) and turn it into a usable form
upon checkout (e.g. download the external content, or decrypt the encrypted
content).
These two filters behave differently, and by default, a filter is taken as the
former, massaging the contents into more convenient shape. A missing filter
driver definition in the config, or a filter driver that exits with a non-zero
status, is not an error but makes the filter a no-op passthru.
You can declare that a filter turns a content that by itself is unusable into a
usable content by setting the filter.<driver>.required configuration
variable to true.
For example, in .gitattributes, you would assign the filter attribute for paths.
Then you would define a "filter.indent.clean" and
"filter.indent.smudge" configuration in your .git/config to specify
a pair of commands to modify the contents of C programs when the source files
are checked in ("clean" is run) and checked out (no change is made
because the command is "cat").
[filter "indent"]
clean = indent
smudge = cat
For best results, clean should not alter its output further if it is run twice
("clean→clean" should be equivalent to "clean"), and
multiple smudge commands should not alter clean's output
("smudge→smudge→clean" should be equivalent to
"clean"). See the section on merging below.
The "indent" filter is well-behaved in this regard: it will not modify
input that is already correctly indented. In this case, the lack of a smudge
filter means that the clean filter
must accept its own output without
modifying it.
If a filter
must succeed in order to make the stored contents usable, you
can declare that the filter is required, in the configuration:
[filter "crypt"]
clean = openssl enc ...
smudge = openssl enc -d ...
required
Sequence "%f" on the filter command line is replaced with the name of
the file the filter is working on. A filter might use this in keyword
substitution. For example:
[filter "p4"]
clean = git-p4-filter --clean %f
smudge = git-p4-filter --smudge %f
Interaction between checkin/checkout attributes
In the check-in codepath, the worktree file is first converted with filter
driver (if specified and corresponding driver defined), then the result is
processed with ident (if specified), and then finally with text (again, if
specified and applicable).
In the check-out codepath, the blob content is first converted with text, and
then ident and fed to filter.
Merging branches with differing checkin/checkout attributes
If you have added attributes to a file that cause the canonical repository
format for that file to change, such as adding a clean/smudge filter or
text/eol/ident attributes, merging anything where the attribute is not in
place would normally cause merge conflicts.
To prevent these unnecessary merge conflicts, git can be told to run a virtual
check-out and check-in of all three stages of a file when resolving a
three-way merge by setting the merge.renormalize configuration variable. This
prevents changes caused by check-in conversion from causing spurious merge
conflicts when a converted file is merged with an unconverted file.
As long as a "smudge→clean" results in the same output as a
"clean" even on files that are already smudged, this strategy will
automatically resolve all filter-related conflicts. Filters that do not act in
this way may cause additional merge conflicts that must be resolved
manually.
Generating diff text¶
diff
The attribute diff affects how
git generates diffs for particular files.
It can tell git whether to generate a textual patch for the path or to treat
the path as a binary file. It can also affect what line is shown on the hunk
header @@ -k,l +n,m @@ line, tell git to use an external command to generate
the diff, or ask git to convert binary files to a text format before
generating the diff.
Set
A path to which the diff attribute is set is
treated as text, even when they contain byte values that normally never appear
in text files, such as NUL.
Unset
A path to which the diff attribute is unset
will generate Binary files differ (or a binary patch, if binary patches are
enabled).
Unspecified
A path to which the diff attribute is
unspecified first gets its contents inspected, and if it looks like text, it
is treated as text. Otherwise it would generate Binary files differ.
String
Diff is shown using the specified diff driver.
Each driver may specify one or more options, as described in the following
section. The options for the diff driver "foo" are defined by the
configuration variables in the "diff.foo" section of the git config
file.
Defining an external diff driver
The definition of a diff driver is done in gitconfig, not gitattributes file, so
strictly speaking this manual page is a wrong place to talk about it.
However...
To define an external diff driver jcdiff, add a section to your $GIT_DIR/config
file (or $HOME/.gitconfig file) like this:
[diff "jcdiff"]
command = j-c-diff
When git needs to show you a diff for the path with diff attribute set to
jcdiff, it calls the command you specified with the above configuration, i.e.
j-c-diff, with 7 parameters, just like GIT_EXTERNAL_DIFF program is called.
See
git(1) for details.
Defining a custom hunk-header
Each group of changes (called a "hunk") in the textual diff output is
prefixed with a line of the form:
This is called a
hunk header. The "TEXT" portion is by default
a line that begins with an alphabet, an underscore or a dollar sign; this
matches what GNU
diff -p output uses. This default selection however is
not suited for some contents, and you can use a customized pattern to make a
selection.
First, in .gitattributes, you would assign the diff attribute for paths.
Then, you would define a "diff.tex.xfuncname" configuration to specify
a regular expression that matches a line that you would want to appear as the
hunk header "TEXT". Add a section to your $GIT_DIR/config file (or
$HOME/.gitconfig file) like this:
[diff "tex"]
xfuncname = "^(\\\\(sub)*section\\{.*)$"
Note. A single level of backslashes are eaten by the configuration file parser,
so you would need to double the backslashes; the pattern above picks a line
that begins with a backslash, and zero or more occurrences of sub followed by
section followed by open brace, to the end of line.
There are a few built-in patterns to make this easier, and tex is one of them,
so you do not have to write the above in your configuration file (you still
need to enable this with the attribute mechanism, via .gitattributes). The
following built in patterns are available:
•
bibtex suitable for files with BibTeX coded references.
•
cpp suitable for source code in the C and C++ languages.
•
csharp suitable for source code in the C# language.
•
fortran suitable for source code in the Fortran language.
•
html suitable for HTML/XHTML documents.
•
java suitable for source code in the Java language.
•
matlab suitable for source code in the MATLAB language.
•
objc suitable for source code in the Objective-C language.
•
pascal suitable for source code in the Pascal/Delphi language.
•
perl suitable for source code in the Perl language.
•
php suitable for source code in the PHP language.
•
python suitable for source code in the Python language.
•
ruby suitable for source code in the Ruby language.
•
tex suitable for source code for LaTeX documents.
Customizing word diff
You can customize the rules that git diff --word-diff uses to split words in a
line, by specifying an appropriate regular expression in the
"diff.*.wordRegex" configuration variable. For example, in TeX a
backslash followed by a sequence of letters forms a command, but several such
commands can be run together without intervening whitespace. To separate them,
use a regular expression in your $GIT_DIR/config file (or $HOME/.gitconfig
file) like this:
[diff "tex"]
wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"
A built-in pattern is provided for all languages listed in the previous
section.
Performing text diffs of binary files
Sometimes it is desirable to see the diff of a text-converted version of some
binary files. For example, a word processor document can be converted to an
ASCII text representation, and the diff of the text shown. Even though this
conversion loses some information, the resulting diff is useful for human
viewing (but cannot be applied directly).
The textconv config option is used to define a program for performing such a
conversion. The program should take a single argument, the name of a file to
convert, and produce the resulting text on stdout.
For example, to show the diff of the exif information of a file instead of the
binary information (assuming you have the exif tool installed), add the
following section to your $GIT_DIR/config file (or $HOME/.gitconfig file):
[diff "jpg"]
textconv = exif
Note
The text conversion is generally a one-way conversion; in this example, we lose
the actual image contents and focus just on the text data. This means that
diffs generated by textconv are
not suitable for applying. For this
reason, only git diff and the git log family of commands (i.e., log,
whatchanged, show) will perform text conversion. git format-patch will never
generate this output. If you want to send somebody a text-converted diff of a
binary file (e.g., because it quickly conveys the changes you have made), you
should generate it separately and send it as a comment
in addition to
the usual binary diff that you might send.
Because text conversion can be slow, especially when doing a large number of
them with git log -p, git provides a mechanism to cache the output and use it
in future diffs. To enable caching, set the "cachetextconv" variable
in your diff driver’s config. For example:
[diff "jpg"]
textconv = exif
cachetextconv = true
This will cache the result of running "exif" on each blob
indefinitely. If you change the textconv config variable for a diff driver,
git will automatically invalidate the cache entries and re-run the textconv
filter. If you want to invalidate the cache manually (e.g., because your
version of "exif" was updated and now produces better output), you
can remove the cache manually with git update-ref -d refs/notes/textconv/jpg
(where "jpg" is the name of the diff driver, as in the example
above).
Choosing textconv versus external diff
If you want to show differences between binary or specially-formatted blobs in
your repository, you can choose to use either an external diff command, or to
use textconv to convert them to a diff-able text format. Which method you
choose depends on your exact situation.
The advantage of using an external diff command is flexibility. You are not
bound to find line-oriented changes, nor is it necessary for the output to
resemble unified diff. You are free to locate and report changes in the most
appropriate way for your data format.
A textconv, by comparison, is much more limiting. You provide a transformation
of the data into a line-oriented text format, and git uses its regular diff
tools to generate the output. There are several advantages to choosing this
method:
1.Ease of use. It is often much simpler to
write a binary to text transformation than it is to perform your own diff. In
many cases, existing programs can be used as textconv filters (e.g., exif,
odt2txt).
2.Git diff features. By performing only the
transformation step yourself, you can still utilize many of git’s diff
features, including colorization, word-diff, and combined diffs for
merges.
3.Caching. Textconv caching can speed up
repeated diffs, such as those you might trigger by running git log -p.
Marking files as binary
Git usually guesses correctly whether a blob contains text or binary data by
examining the beginning of the contents. However, sometimes you may want to
override its decision, either because a blob contains binary data later in the
file, or because the content, while technically composed of text characters,
is opaque to a human reader. For example, many postscript files contain only
ascii characters, but produce noisy and meaningless diffs.
The simplest way to mark a file as binary is to unset the diff attribute in the
.gitattributes file:
This will cause git to generate Binary files differ (or a binary patch, if
binary patches are enabled) instead of a regular diff.
However, one may also want to specify other diff driver attributes. For example,
you might want to use textconv to convert postscript files to an ascii
representation for human viewing, but otherwise treat them as binary files.
You cannot specify both -diff and diff=ps attributes. The solution is to use
the diff.*.binary config option:
[diff "ps"]
textconv = ps2ascii
binary = true
merge
The attribute merge affects how three versions of a file are merged when a
file-level merge is necessary during git merge, and other commands such as git
revert and git cherry-pick.
Set
Built-in 3-way merge driver is used to merge
the contents in a way similar to merge command of RCS suite. This is
suitable for ordinary text files.
Unset
Take the version from the current branch as
the tentative merge result, and declare that the merge has conflicts. This is
suitable for binary files that do not have a well-defined merge
semantics.
Unspecified
By default, this uses the same built-in 3-way
merge driver as is the case when the merge attribute is set. However, the
merge.default configuration variable can name different merge driver to be
used with paths for which the merge attribute is unspecified.
String
3-way merge is performed using the specified
custom merge driver. The built-in 3-way merge driver can be explicitly
specified by asking for "text" driver; the built-in "take the
current branch" driver can be requested with "binary".
Built-in merge drivers
There are a few built-in low-level merge drivers defined that can be asked for
via the merge attribute.
text
Usual 3-way file level merge for text files.
Conflicted regions are marked with conflict markers
<<<<<<<, ======= and >>>>>>>. The
version from your branch appears before the ======= marker, and the version
from the merged branch appears after the ======= marker.
binary
Keep the version from your branch in the work
tree, but leave the path in the conflicted state for the user to sort
out.
union
Run 3-way file level merge for text files, but
take lines from both versions, instead of leaving conflict markers. This tends
to leave the added lines in the resulting file in random order and the user
should verify the result. Do not use this if you do not understand the
implications.
Defining a custom merge driver
The definition of a merge driver is done in the .git/config file, not in the
gitattributes file, so strictly speaking this manual page is a wrong place to
talk about it. However...
To define a custom merge driver filfre, add a section to your $GIT_DIR/config
file (or $HOME/.gitconfig file) like this:
[merge "filfre"]
name = feel-free merge driver
driver = filfre %O %A %B
recursive = binary
The merge.*.name variable gives the driver a human-readable name.
The ‘merge.*.driver` variable’s value is used to construct a command
to run to merge ancestor’s version (%O), current version (%A) and the
other branches’ version (%B). These three tokens are replaced with the
names of temporary files that hold the contents of these versions when the
command line is built. Additionally, %L will be replaced with the conflict
marker size (see below).
The merge driver is expected to leave the result of the merge in the file named
with %A by overwriting it, and exit with zero status if it managed to merge
them cleanly, or non-zero if there were conflicts.
The merge.*.recursive variable specifies what other merge driver to use when the
merge driver is called for an internal merge between common ancestors, when
there are more than one. When left unspecified, the driver itself is used for
both internal merge and the final merge.
conflict-marker-size
This attribute controls the length of conflict markers left in the work tree
file during a conflicted merge. Only setting to the value to a positive
integer has any meaningful effect.
For example, this line in .gitattributes can be used to tell the merge machinery
to leave much longer (instead of the usual 7-character-long) conflict markers
when merging the file Documentation/git-merge.txt results in a conflict.
Documentation/git-merge.txt conflict-marker-size=32
Checking whitespace errors¶
whitespace
The core.whitespace configuration variable allows you to define what
diff
and
apply should consider whitespace errors for all paths in the
project (See
git-config(1)). This attribute gives you finer control per
path.
Set
Notice all types of potential whitespace
errors known to git. The tab width is taken from the value of the
core.whitespace configuration variable.
Unset
Do not notice anything as error.
Unspecified
Use the value of the core.whitespace
configuration variable to decide what to notice as error.
String
Specify a comma separate list of common
whitespace problems to notice in the same format as the core.whitespace
configuration variable.
Creating an archive¶
export-ignore
Files and directories with the attribute export-ignore won’t be added to
archive files.
export-subst
If the attribute export-subst is set for a file then git will expand several
placeholders when adding this file to an archive. The expansion depends on the
availability of a commit ID, i.e., if
git-archive(1) has been given a
tree instead of a commit or a tag then no replacement will be done. The
placeholders are the same as those for the option --pretty=format: of
git-log(1), except that they need to be wrapped like this:
$Format:PLACEHOLDERS$ in the file. E.g. the string $Format:%H$ will be
replaced by the commit hash.
Packing objects¶
delta
Delta compression will not be attempted for blobs for paths with the attribute
delta set to false.
encoding
The value of this attribute specifies the character encoding that should be used
by GUI tools (e.g.
gitk(1) and
git-gui(1)) to display the
contents of the relevant file. Note that due to performance considerations
gitk(1) does not use this attribute unless you manually enable per-file
encodings in its options.
If this attribute is not set or has an invalid value, the value of the
gui.encoding configuration variable is used instead (See
git-config(1)).
USING MACRO ATTRIBUTES¶
You do not want any end-of-line conversions applied to, nor textual diffs
produced for, any binary file you track. You would need to specify e.g.
but that may become cumbersome, when you have many attributes. Using macro
attributes, you can define an attribute that, when set, also sets or unsets a
number of other attributes at the same time. The system knows a built-in macro
attribute, binary:
Setting the "binary" attribute also unsets the "text" and
"diff" attributes as above. Note that macro attributes can only be
"Set", though setting one might have the effect of setting or
unsetting other attributes or even returning other attributes to the
"Unspecified" state.
DEFINING MACRO ATTRIBUTES¶
Custom macro attributes can be defined only in the .gitattributes file at the
toplevel (i.e. not in any subdirectory). The built-in macro attribute
"binary" is equivalent to:
EXAMPLE¶
If you have these three gitattributes file:
(in $GIT_DIR/info/attributes)
a* foo !bar -baz
(in .gitattributes)
abc foo bar baz
(in t/.gitattributes)
ab* merge=filfre
abc -foo -bar
*.c frotz
the attributes given to path t/abc are computed as follows:
1.By examining t/.gitattributes (which is in
the same directory as the path in question), git finds that the first line
matches. merge attribute is set. It also finds that the second line matches,
and attributes foo and bar are unset.
2.Then it examines .gitattributes (which is
in the parent directory), and finds that the first line matches, but
t/.gitattributes file already decided how merge, foo and bar attributes should
be given to this path, so it leaves foo and bar unset. Attribute baz is
set.
3.Finally it examines
$GIT_DIR/info/attributes. This file is used to override the in-tree settings.
The first line is a match, and foo is set, bar is reverted to unspecified
state, and baz is unset.
As the result, the attributes assignment to t/abc becomes:
foo set to true
bar unspecified
baz set to false
merge set to string value "filfre"
frotz unspecified
SEE ALSO¶
git-check-attr(1).
GIT¶
Part of the
git(1) suite